Apparatus for inductively heating parts of cylindrical workpieces



Feb. 10, 1970 F. REINKE ETAL APPARATUS FOR INDUCTIVELY HEATING'PARTS 0F CYLINDRICAL WORKPIECES 1967 2 Sheets-Sheet 1 Filed March 5,

Feb. 10, 1970 F. REINKE ETAL 3,494,604

APPARATUS FOR INDUCTIVELY HEATING PARTS OF CYLINDRICAL WORKPIECES Filed March 5. 1967 H 2 Sheets-Sheet 2 'lgepl rs Moo United States Patent 3,494,604 APPARATUS FOR INDUC'I'IVELY HEATING PARTS OF CYLlNDRICAL WORKPIECES Friedhelm Reinke, Remscheid, Hermann Kuhlbars, Remscheid-Luttringhausen, and Edgar Stengel, Wuppertal- Hahnerberg, Germany, assignors to AEG-Elotherm G.m.b.H., Remscheid-Hasten, Germany Filed Mar. 3, 1967, Ser. No. 620,398 Claims priority, applicati50i17(7};rmany, Mar. 8, 1966, Int. Cl. C21d 1/66 US. Cl. 2664 5 Claims ABSTRACT OF THE DISCLOSURE Apparatus for inductively heating parts of workpieces, particularly camshafts, of the type in which the workpieces are held in a pair of spiders adapted for predetermined rotary movement, in which means are provided for vertical reciprocating movement of the inductor in response to movement of the workpieces.

For heat treating such workpieces it has previously been proposed to provide pairs of spiders adapted for predetermined rotary movement and provided with centre elements between which the workpiece can be mounted for conveying it to the treating stations and to the quenching bath.

Known arrangements of this kind have certain disadvantages including the fact that the drive and control shafts of the mechanism are below the level of the liquid in the quenching bath, and therefore require bushings and liquid-tight seals. Difiiculties also arise because the workpieces are set up between the centre elements of the spiders when they are already within range of the inductor. Difficulties in mounting the workpieces in this way may damage the inductor.

These and other disadvantages are overcome by the invention, which prevents loss of time in performing the electrical switching operations by mechanically coupling the spiders with the inductor and its transformer so as to undergo accurately synchronised motions therewith, and which also permits the workpieces to be immersed in the quenching fluid for different periods of time.

The invention consists of apparatus for inductively heating parts of workpieces, of the type in which the workpieces are held in a pair of spiders adapted for predetermined rotary movement provided with centre elements between which each workpiece is gripped and conveyed to the treating stations, including a quenching bath, the improvement which comprises a slotted disc affixed to the pair of spiders, the said slotted disc having two mutually right-angled intersecting slots co-operating with a cam roller engaging therein the movement of which is guided by a crank and rocker linkage to described a loop comprising two mutually perpendicular portions of the said right-angled slots, and actuating means for vertically reciprocating the inductor and its associated transformer in response to movement of the said cam roller, comprising a lever pivoted on the axle of the cam roller and pivotally engaged with carrying means for the said inductor.

The spiders are preferably preset to rotate and stop in two quenching stations at which the workpiece is imr 3,494,604 Ice Patented Feb. 10, 1970 mersed in the quenching bath, from each of which stations the workpieces can be removed by a parallel crank linkage provided with two V rests and conveyed to a lifting beam conveyor. According to whether the workpiece is released by the centre elements at the first or the second of the two quenching stations, the quenching times can be varied, e.g. practically doubled.

The centre elements for holding the workpieces are rotatable in the arms of the spiders and are axially springloaded. This arrangement permits the workpieces to be released as desired, and to be gripped before they enter the inductor.

For removing the workpieces from the apparatus and for submitting them to a final heat-treatment, a lifting beam conveyor with lifting hooks is provided. The lifting beam may be driven by two cranks of relatively adjustable phase so that the lifting hooks for the workpieces move in a Lissajous curve substantially in the form of a horizontal figure-of-eight. An inductor is associated with one of the V rests provided in the fixed beam of the conveyor. During their transportation the workpieces are automatically conveyed into this inductor and gripped between centre elements when they reach the said V-rest in the fixed beam. The workpiece can therefore be rotated about its own axis whilst it is being heated and quenched at this station. The lifting beam conveyor, which should be constructed to permit it to accept workpieces from the aforesaid parallel crank linkage, may be constructed to be of suflicient length to move the delivery point of the heat-treated workpieces suificiently far away from the machine to provide adequate space for the accommodation of driving motors and so forth.

Apparatus according to the invention effectively overcomes the drawbacks of known apparatus of the specified kind. Moreover, it is of simple and straightforward construction and not liable to develop faults in operation.

An embodiment of the invention is hereinafter described and illustrated in the accompanying drawings, of which FIGURE 1 is a side elevation, some of the sheet metal casing being removed, and

FIGURE 2 is an end elevation showing the spider but omitting equipment for feeding and removing workpieces.

The illustrated embodiment is intended for use in heat treating camshafts for internal combustion engines. The cams are all simultaneously heated and quenched for surface hardening, and an eccentric on the camshaft is separately heated in an additional heating station and then quenched.

Referring to the drawings, a frame 1 contains a quenching bath 2, and a pair of spiders together indicated at 4 for transporting the work pieces between arms thereof, located above the surface 3 of the bath. Above the spider is a vertically movable slide 5 which carries a transformer (not shown), and an inductor 6. The workpieces are fed to the spider 4 by a conveyor chain 7 and they are removed from the spider, after having been treated, by a parallel crank linkage '8 which transfers them to a lifting beam conveyor 9. The latter carries them out of the apparatus to a hardening station 10. In the embodiment illustrated in the drawings, the surface of the eccentric is heated and quenched in this hardening station. The workpieces then slide down a chute 11 to a point whence they can be conveniently transported away.

The sequence of events for treating the workpieces vith the apparatus according to the invention is as Follows:

A pair of spiders 12 is mounted on a shaft 13 to one :nd of which an overhung slotted disc 14 is firmly keyed. \s will be understood from FIGURE 1 the disc 14 is rovided with two mutually perpendicular cam slots 15 and 16, extending across the said disc. A cam roller [7 works in this slot, and moves around a loop 18 generated by a crank and rocker linkage, the said linktge comprising a crank 19 driven by a geared motor 20, a link 21 and a rocker 22. The loop 18 is traversed )y the cam roller 17, in the illustrated embodiment, I

lfter the roller has ascended the oblique slot 16 in the :lotted disc 14 and thereby the work mounted between he centre elements is conveyed from station 23 to the mating station 24. When the work reaches the heating tation 24 the cam roller 17 returns to the intersection 55 of the mutually perpendicular cam slots and 16, 1nd cannot ascend the slot 16 but follows slot 16 in the lirection of rotation of the disc 14 until said linkage is )perated again by the motor 20. Pivotably attached to he axle of cam roller 17 is a lever 26 which is articuated to the movable slide 5 for lifting and lowering he transformer (not shown) and the inductor 6. The Lrrangement is such that the inductor is lifted whilst he work W is being conveyed from one station to the text.

When a workpiece has been deposited by the feeder :hain 7 in the receiving V 27 at the mounting station 53, the centre elements 28 which had previously been 'etracted are reclosed to grip the workpiece between hem. The said 'closure of the centre elements is operable Jy a pneumatic cylinder 29. For rotating the workpiece N during the processes of heating and quenching, rota- :ion can be imparted to the said centre elements by In epicyclic gearing indicated at 30.

The gripped workpiece W is moved into the heating :tation 24 whilst the inductor 6 and its transformer are ifted by the lever 26. As soon as the workpiece reaches he heating station the inductor 6- descends into workng position as the cam roller 17 descends to the inter- :ection 25 in the slotted disc 14 and, whilst the workiece W continues to revolve about its own axis, it is mated to the required temperature. A relay subsequently :tarts up the motor and its associated crank and 'ocker linkage, causing the cam roller 17 to travel tovard station 20, as shown in FIGURE 1, in the slotted lisc 14. The workpiece W descends into a first quenching station 31 during peripheral motion of the cam roller [7 along the path 18, from whence it can be removed f a simple immersion is desired. Alternatively, if the mmersion period is to be prolonged to approximately wice this time, the centre elements 28 can be prevented from releasing the workpiece at the hardening station i1, and from opening until the workpiece W has been noved to the second quenching station 32. The operation )f the centre elements to achieve the desired location of he workpiece may be actuated by pneumatic cylinders which are electrically controllable as desired.

In order to monitor the rotation of the workpiece luring the heating and quenching processes a revolution nonitor 33 is provided which is coupled by magnets 34 o the centre axles, and thus indicates whether the centre :lements are rotating as required.

It will be understood from the drawings that all nachine elements which pass through the walls of the ank containing the quenching liquid 2 are located above he surface 3 of the bath so that no seals and the like ire needed Where such shafts pass through the Walls, and further all moving parts are outside the bath.

The vertically movable slide 5 is guided by rollers 55 which ride up and down columns 36. For balancing ts weight the slide is suspended from a spring 37. The :hain 38 runs over a chain wheel 39.

For removing the workpiece W optionally from the quenching station 31 or 32 a linkage in the form of a parallel crank linkage is provided. In the embodiment illustrated in the drawings, this parallel crank linkage comprises cranks 40, 40' together with bars 41 and 42, driven by a motor (not shown), by rotation of the pivot at 43. This linkage has two V-rests 44 and 45 separated by a distance equal to the linear distance between the two quenching stations 31 and 32. The V-rests move along arcs 46 and 47 indicated by dot-dash lines and they therefore convey a workpiece W from 31 to point 48, whereas a workpiece W located at 32 is conveyed to point 49. Whether the linkage removes a workpiece from quenching station 31 or 32 depends upon the station at which the centre elements have been withdrawn to release the workpiece.

The two'points 48 and 49 are V-rests in the fixed beam 50 of a lifting beam conveyor comprising a lifting beam 51 armed with hooks 52 for lifting the workpieces. The lifting beam and hence the hooks 52 perform a motion defined by a Lissajous curve in the form of a horizontal figure-of-eight 53. By being repeatedly deposited on the fixed beam '50 and lifted again to the next V the workpieces are conveyed to the hardening station at 10, where in the embodiment illustrated in the drawings the eccentrics on the cam shafts are hardened. At this station the workpieces W are likewise gripped between centre elements and rotated about their axes.

For generating the described movement of the lifting beam 51 mechanism is provided which is driven by the geared motor 20 through a chain 54 and chain wheel 55. The chain wheel 55 drives a gear wheel 56 which in turn meshes with two intermediate wheels 57 for driving cranks through gear wheels 58. The cranks raise and lower a cross bar 60, whereas a pin 61 on gear wheel 56 slides in a slot 62 and generates a simultaneous to and fro movement of the cross bar 60. The relative phasing of the two reciprocations generates the said Lissajous curve. In order to permit the workpieces W that have been collected from the quenching station 31 or 32 and carried to the fixed beam '50 to be deposited in the V-rests of the beam, the V-rests themselves may be hingeably raised. They are thus tilted up about their hinges at 48' or 49 when the workpiece approaches the bar on the transferring parallel crank linkage, and tilted down again when the linkage begins to descend, thus permitting the workpieces W to be received into the V-slots.

What is claimed is:

1. Apparatus for inductively heating parts of workpieces, of thetype in which the workpieces are held in a pair of spiders adapted for predetermined rotary movement provided with centre elements between which each workpiece is gripped and coveyed to the treating stations including a quenching bath; the improvement which comprises a slotted disc affixed to the pair of spiders, the said slotted disc having two mutually right-angled inter secting slots co-operating with a cam roller engaging therein the movement of which is guided by a crank and rocker linkage to describe a loop comprising two mutually perpendicular portions of the said right-angled slots, and actuating means forvertically reciprocating the inductor and its associatedtransformer in response to movement of the said cam roller, comprising a lever pivoted on the axle of the cam roller and pivotally engaged with carrying means for the said inductor.

2. Apparatus according to claim 1, in which the centre elements for holding the workpieces are rotatable and axially spring-loaded.

3. Apparatus according to claim 1, in which the said spiders are moved to stop in two positions in which the workpiece is immersed in the quenching bath, and whence a parallel crank linkage is provided with two V-rests and which is adapted to transfer the workpieces from a quenching station to a lifting beam conveyor.

4. Apparatus according to claim 1, in which the lifting beam is provided with hooks and driven by two cranks of relatively adjustable phase to provide a movement of a Lissajous curve substantially in the form of a horizontal figure-of-eight.

5. Apparatus according to claim 1, in which one of the V-rests in the fixed beam of the lifting beam conveyor is associated with an inductor into which the workpieces are automatically conveyed to be gripped between centre elements when they are deposited on the said V-rest.

References Cited UNITED STATES PATENTS Campbell et al. 2664 X Campbell.

Dammert et al.

Barkley et al. 2664 Cary 2664 WILLIAM J. STEPHENSON, Primary Examiner JOHN S. BROWN, Assistant Examiner 

